1. Field of the Invention
This invention relates to a device for reading positional information on photographic films which is used for checking the frame number and the position of each image frame of a film by reading positional information provided for each image frame.
2. Description of the Related Art
Generally, photographic printing apparatuses are so designed that a photographic film, such as a negative film or a positive film, is set in a negative carrier, and is then brought to a printing position in the body of the printing apparatus so as to print on print paper the images on the film. Attached to the negative carrier is a feeding device which serves to feed an elongated negative film in the longitudinal direction and successively position the image frames thereon in the printing position to allow printing to be effected.
A mark indicative of positional information is provided for each image frame at a position in the vicinity thereof, the relative position of each mark with respect to the corresponding image frame being the same throughout the film. Any image frame whose image is to be printed can be selected by reading the positional information allotted thereto by means of a sensor. That image frame is automatically brought to the printing position by virtue of notches formed on the film in correspondence with the image frames. Positional information is provided in the form of bar codes which are arranged in a longitudinal direction of the film in correspondence with the frame numbers allotted to the frames in a predetermined sequence. By entering a desired frame number, the operator can search for the bar code corresponding to that frame number. Accordingly, frame positioning can be easily performed even when image frames are to be printed in a discontinuous order, which can be the case at the time of an order for reprints or extra prints.
However, if an error occurs in the reading of bar codes, an image frame having a frame number not corresponding to the one entered may be placed in the printing position. It can even happen that a specified frame number cannot be found. To prevent such mulfunctioning of the printing apparatus due to reading errors, the operator has to check the frame number each time an image frame is placed in the printing position to make sure that the correct image frame has been placed in position, resulting in poor operational efficiency.